Over at Tamino's there is an interesting analysis of sea levels - since we discussed it at some length here it is worth a visit to read.
http://tamino.wordpress.com/2012/09/26/unnatural-hazards/#more-5663

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

I haven't read Hansen & Sato, but Joe Romm's site gave this quote:
"BAU scenarios result in global warming of the order of 3-6°C. It is this scenario for which we assert that multi-meter sea level rise on the century time scale are not only possible, but almost dead certain. "
and
"What about the intermediate scenario, EU2C? We have presented evidence in this paper that prior interglacial periods were less than 1°C warmer than the Holocene maximum. If we are correct in that conclusion, the EU2C scenario implies a sea level rise of many meters. It is difficult to predict a time scale for the sea level rise, but it would be dangerous and foolish to take such a global warming scenario as a goal."
Yes, you are correct, Tony.
I would interpret that to mean EU2C to be at least 3 meters for an undetermined time, and BAU to mean 2 or more meters by 2112.
In terms of planning for infrastructure, it leave a pretty wide range between Hansen and the IPCC AR4 range of .18-.59 meters by 2099, depending on scenario - and not a lot of time to prepare if it is closer to Hansen than IPCC AR4.

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

Djprice537:
The estimate of the percent of the worlds population to be relocated with a 10 meter sea level increase is from Deborah Balk, the acting associate director of the Institute for Demographic Research, in a study they did in 2007.
I do know something about infrastructure, I'm a Professional Civil Engineer with 35 years of practice involving infrastructure design and relocation. The task of relocating 5-10% of the worlds' population would be immense, and 80 to 100 years for planning and implementation is an incredibly short time period for something of this magnitude. Believe me, I do not underestimate the task.
The issue with models I was alluding to was that the probability of a sea level increase of x meters by a certain date is necessary information. When we design a dam or a levee, we look at the risk associated with failure given a set of probabilities. On a minor dam where the risk of death or damage is small downstream, we might design for a 0.5% annual probability of failure. A larger dam, where there is higher risk downstream, would be designed to a much lower probability of failure. The hydrologic and hydraulic modeling provides the basis for the design.
I see the climate, and especially sea level, models as serving the same purpose. If the risk of a 10 meter increase is extremely small, we do not have, nor should we, allocate resources to plan and implement a process to accommodate that. If the risk of a 2 meter increase is high over the next 90 years, we must devote the resources for that possibility.
I know that climate models are much more complex than the well established H & H models, but great effort needs to be made to improve and verify the models to avoid either wasting a limited amount of resources, or worse, failing to provide those resources when needed.

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

Thanks Al,
With Hansen predicting up to 5m, and recognizing the arctic ice melt models appear overly conservative, it's a subject I'll need to look at closer.
Adaption to 2m will be expensive, but nothing like 5m.

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

The relocation of 10% of the worlds population is an unimaginable task, and I don't know how it would be possible to allocate the resources to accomplish that task.
What we see in the Arctic indicates to me that it is possible, though it still seems unlikely, for Greenland and WAIS to contribute sufficient melt to see a 5-10 meter sea level increase within the century. I think the modeling is of critical importance to see if climate change can (will?) impact Greenland and WAIS that amount. If the models start to provide evidence of a chance of a 10 meter increase in sea level, then the Herculean task of planning for the relocating 5-10% of the worlds population and the infrastructure to service them would need to be done. Not to mention the changes to the water and food supply chain that would have to occur concurrently. It makes a real difference relocating, say, 2% of the worlds people verses 10%.

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

All models are wrong, but some are useful, as the saying goes. However, when looking at how Arctic sea ice decline is modeled, one might be tempted to say that all sayings are useful, but some are wrong. To be fair, I should be the last person taking a piss at climate models. Hundreds of brill...

It looks like the ice arch in at the southern end of Nares Strait has started to collapse, according to yesterday's satellite image from LANCE-MODIS: This break-up is occuring 10 days later than last year. Back then it took about two weeks for all of the ice to start moving across the entire s...

While sunning myself on the unusually ice free shores of Lake Michigan, it feels like spring is imminent. But I think we've got another 30 days for increased area and am guessing at 3.15 million km2. That would put it at day 61-63.
A virtual tie with last year.

EDIT Neven: There's a poll in the right hand bar running until February 8th for predicting the Cryosphere Today maximum sea ice area number. See details below. Don't be afraid to share your prediction in the comments. :-) ----- Post by guest author crandles: It doesn't look like the area maxi...

I know I've received far more value from Neven and the other contributors to this blog than the small amount I was able to donate. Thank you all.
I believe the distribution as shown above is very fair. The Darfur Stoves Project certainly seems worthy.
Yazzur

This post has taken me a bit longer than anticipated, because I really had a hard time picking a suitable island in the South Pacific to be bought with the donations that came in through the tip jar. But then I had a streak of conscience and ahem, realized I don't want to be on an island in th...

Towards the end of last melting season we had a lot of fun speculating about large patches of ice getting separated from the main pack. Well, at least I did. So much so that I wrote an article about it, called Breaking away from the pack. Much of the ice seemed to be very thin at the time and th...

Towards the end of last melting season we had a lot of fun speculating about large patches of ice getting separated from the main pack. Well, at least I did. So much so that I wrote an article about it, called Breaking away from the pack. Much of the ice seemed to be very thin at the time and th...

I've fiddled long enough now with this new and simple design, so here we go: There's a column to the right and left now. There's a link to the Arctic Daily Graphs page in the navigation bar on top. You can mail me through a link in the navigation bar (I check this account every other day). Ther...

Based on physical observations, I would be very surprised if area and thickness were a linear relationship. On the Great Lakes, it's not unusual to see a large area of ice disappear in the matter of a few days.
It's often a quick ice out, Lake Erie can essentially lose the ice cover in a week. From observing ice out on smaller lakes, it more often is such that the ice continues to thin over a whole lake until winds break it up in a day. Although the seas are not the Great Lakes, it would seem it would be similar, with the ice thinning over large areas until such point it was thin enough for a weather occurrence to break up a relatively large area in a very short period of time.

With Bfraser's guest blog being posted yesterday and the Arctic sea ice approaching maximum extent (I think, IJIS hasn't updated the past few days), I think I can safely call an end to our semi-hibernation. As said before I'm still waiting for my virtual credit card to get cleared after which I ...

The other open thread comprised more than 100 comments, so here's a new one. There was some talk about the Alarmist's Dilemma, and I'm sure it won't be the last. I was planning on upgrading the blog to a paid version, but TypePad only allows it when one has a credit card, so I have to get one fi...

Nice summary Yooper, I was in the Keweenaw for 5 years, so I'm still bit of a Yooper.
Although not arctic ice, for those interested, here are ice maps for the Great Lakes:
http://www.glerl.noaa.gov/res/glcfs/glcfs.php?lake=l&ext=ice&type=N&hr=00
Even with warmer than normal water in the Great Lakes, our lake effect snowfall not as much as usual. Lake Michigan water level is 19" below the January average, 9" above record lows, and 53" below record high.
Yazzur

The other open thread comprised more than 100 comments, so here's a new one. There was some talk about the Alarmist's Dilemma, and I'm sure it won't be the last. I was planning on upgrading the blog to a paid version, but TypePad only allows it when one has a credit card, so I have to get one fi...

"Daniel, I'm guessing from the tag that you're from "Yooper" Michigan?What news from the Great Lakes this winter? Ice free yet?"
I'm a troll (Michigan definition - living "under", or south the Mackinac bridge,), on the little finger of Michigan, and so far, Lake Michigan is ice free, but that is not really unusual for this time of year. There has been a gradual reduction in freeze over on the larger bays over the past 20 years, with my local Grand Traverse Bay not freezing several times in the past 10 years, historically it's unusual for it to not freeze.
Who's the Hudson Bay expert here? Has it ever not frozen over?
Yazzur

The other open thread comprised more than 100 comments, so here's a new one. There was some talk about the Alarmist's Dilemma, and I'm sure it won't be the last. I was planning on upgrading the blog to a paid version, but TypePad only allows it when one has a credit card, so I have to get one fi...

Is anybody watching the far northeastern corner of Greenland (near Kap Bridgman?), and the large ice chunks breaking off? I thought this area was mostly multi-year ice. It looks like several large cracks are starting to open up in that area.

I'm regularly writing updates on the current sea ice extent (SIE) as reported by IJIS (a joint effort of the International Arctic Research Center and the Japan Aerospace Exploration Agency) and compare it to the sea ice extents in the period 2006-2009. The IJIS graph is favoured by almost everyo...